Device for degassing a liquid

ABSTRACT

The invention relates to a device for degassing liquids, while applying a cyclone, in particular for removing an inert gas such as argon from liquid sodium, comprising a cylindrical container provided with a tangential supply duct for the liquid to be degassed, a central discharge for the gas at the upper side of the container, a cyclone mantle and a discharge duct for the degassed liquid, wherein at the inner side of the container wall a horizontal partition is provided that lies under the tangential supply duct of the liquid, at which partition a cylindrical cyclone mantle is attached that is concentrical with this container, which cyclone mantle is open at the upper and lower sides and whose upper edge lies over the supply duct and whose lower edge is situated near the bottom of the container, while at a slight distance under the partition the discharge duct for the degassed liquid is connected to the space between the cyclone inner mantle and the container wall.

United States Patent Wisman et al.

[ Nov. 13, 1973 DEVICE FOR DEGASSING A LIQUID [75 l Inventors: GerritMarinus Wisman; Pieter Adam Van Rijs, both of Apeldoorn, Netherlands[73] Assignee: Nederlandse Organisatie Voor ToegepastNatuurwelenschappelijk Onderzoek Ten Behoeve Van Nijverheld, The Hague,Netherlands 22 Filed: Oct. 8, 1971 21 Appl. No.: 187,828

52 us. c1. ss/204 [51] Int. Cl 801d 19/00 [58] Field oi Search 55/41,52, 66, 92, 55/l9l,204,205;2l0/5l2 [56] References Cited UNITED STATESPATENTS 2,059,522 11/1936 l-lawley 55/D1G. 22 2,835,343 5/1958 Wolff etal 55/66 2,983,331 5/1961 Helslcy, Jr. 55/204 3,088,595 5/1963 Robb55/204 X 3,127,255 3/1964 Winslow 55/204 X 3,359,708 12/1967 Barber55/205 X Primary Examiner--Samih N. Zaharna Assistant Examiner-R. W.Burks Att0rney-Hammond & Littell 5 7 ABSTRACT The invention relates to adevice for degassing liquids, while applying a cyclone, in particularfor removing an inert gas such as argon from liquid sodium, comprising acylindrical container provided with a tangential supply duct for theliquid to be degassed, a central discharge for the gas at the upper sideof the container, a cyclone mantle and a discharge duct for the degassedliquid, wherein at the inner side of the container wall a horizontalpartition is provided that lies under the tangential supply duct of theliquid, at which partition a cylindrical cyclone mantle is attached thatis concentrical with this container, which cyclone mantle is open at theupper and lower sides and whose upper edge lies over the supply duct andwhose lower edge is situated near the bottom of the container, while ata slight distance under the partition the discharge duct for thedegassed liquid is connected to the space between the cyclone innermantle and the container wall.

3 Claims, 2 Drawing Figures Pmmgnanv a 3 ms 3,771,285

SHEET 1 BF 2 DEVICE FOR DEGASSING A LIQUID The invention relates to adevice for degassing liquids while applying a cyclone, in particular forremoving an inert gas such as argon from liquid sodium, to be applied ina cooling circuit of a rapid sodium-cooled reactor.

Devices in which a gas is separated from a liquid with the aid ofcyclonic action are known in the art.

Such cyclones in general consist of a cylindrical or conicalfunnel-shaped container or mantle, tapering downwards, to whichalongside the upper side of the container one or more tangential supplyducts are connected for the liquid to be purified.

Then in the centre at the upper side of the container the discharge pipeis situated for the gas to be separated and then near the lower side ofthe container the discharge for the purified liquid is provided that canbe mounted tangentially or axially to the container, whereas in thelatter case near or in the discharge opening blade-shaped means can beprovided.

Then the separation of the two components, the gas and the liquid, iseffected because the heavy particles of liquid are pushed towards thewall of the cyclone, as a result of the centrifugal force of the mixtureperforming a circular movement within the cyclone, and the lighterparticles of gas are pushed towards the axis of the cyclone.

Hence in the core area of the mantle a vortex pattern is generated inwhich the gas particles can escape from the flow of liquid and can bedischarged upwardly.

These devices known in the art have disadvantages, however.

In the cyclone a strong downwardly directed flow is generated because ofthe throughput flowing through the device. In order to increase theseparation of gas'as much as possible under these conditions a longcyclone has to be used so as to prevent entrainment of gas bubblestowards the liquid discharge. This has the drawback that liquid supplyand discharge ducts come to lie far apart.

Nor have the so-called cones, conical trap discs, applied in thisconnection, that serve to restrict the penetration of the gas bubbles asfar as the bottom of the vortex and to prevent entrainment into the flowof liquid, been found efficient in practice.

In particular the smaller gas bubbles are still entrained downwardly inthe strong flow and stand no chance of rising and escaping via thecentral gas discharge. Moreover, in the core an amount of gas bubblesremains floating constantly.

Since in particular in degassing liquid sodium it should be prevented asmuch as possible that gas particles are entrained in the sodiumdischarge the device known in the art are totally insufficient for theseparation mentioned above.

Now the object of the device according to the invention is to remove theabove-mentioned drawbacks and to provide a device in which also thelighter gas bubbles that are situated in the core area can rise andescape.

With the aid of the device according to the invention further a degasseris obtained in which the length of the degasser can be kept relativelysmall in respect of the diameter with a slight difference in heightbetween the supply and discharge ducts of the liquid to be purified,whereas yet the separation traject necessary for an adequate separationcan be maintained.

Further the device according to the invention is reliable and can handleefficiently great amounts of gas passing through suddenly (peak load).

Therefore, in the device according to the invention at the inner side ofthe cylindrical container of the degasser is provided a horizontalpartition, which lies below the tangential supply duct of the liquid,and to which is connected a cylindrical cyclone inner mantle, which isopen at the bottom and at the top and which is concentrical with thiscontainer, and whose upper edge lies over the supply duct and whoselower edge is situated near the bottom of the container, whereas at aslight distance below the partition the discharge duct for the degassedliquid is connected to the space between the cyclone inner mantle andthe container wall. As a result of this construction of the degasser andthe arrangement shown of the inner mantle and the supply and dischargeducts a good an adequate cyclonic action can be obtained.

The tangential supply into the container or outer mantle of the degasserenables the liquid to be purified to flow into the cyclone space overthe entire upper circumference of the inner cylinder. This results inthe creation of a stable vortex due to the symmetric feed With thisconstruction most gas escapes already directly over the upper edge ofthe inner mantle and passes under the cover plate of the container tothe gas discharge duct.

By placing also the discharge duct for the degassed liquid in the outermantle, while retaining a long flow path, a slight difference in heightbetween the supply and discharge ducts may yet suffice.

With this construction the vortex pattern known at a cyclonic actionwill mainly be formed in the inner mantle.

With the device according to the invention the discharge duct for thegas is situated centrally over the upper edge of this cyclone innermantle, and has a diameter that is considerable smaller than thediameter of this mantle.

The gas bubbles released in the vortex in the centre of the innermantle, therefore, will be able to escape straight upwards via this gasdischarge.

In order to promote the rising movement of the gas bubbles from thevortex area in the device according to the invention in the cycloneinner mantle a central body is mounted, which outwardly is provided withat least one helical rib, which body extends from below the lower edgeof the inner mantle into the discharge duct for the gas.

In the device according to the invention, this helical rib has a coursethat has a direction opposite to the direction of rotation effected bythe tangential supply duct in the liquid to be degassed.

This helical rib causes a delay in velocity in the core area of thevortex, so that the smaller gas bubbles, too, are released from theliquid and rise.

It should be remarked still that with cyclones for gas purification,application of a helical displacer in a central axis is known in theart. Such a displacer, however, then has a totally different functionand serves with the gas purifiers to raise the velocity of the heaviercomponent, so the impurities in the gas, in order to centrifuge theseout before the gas is carried off upwards.

The device according to the invention will be further described belowand elucidated with reference to a drawing, in which an embodiment ofthe device is shown.

In this drawing FIG. 1 gives a longitudinal section of the device andFIG. 2 a cross-section along line IIII in FIG. 1.

In FIG. 1, l is the cylindrical container of the degasser, which isprovided with flange 2 for connecting cover lid 4 with bolts 5 andflange 3 for connecting bottom plate 6 with bolts 7.

Container 1 is provided with a tangential supply duct 8 for the liquidto be degassed and a tangential discharge duct 9 for the degassedliquid.

In cover lid 4 there is provided central discharge duct 10 for the gastowards gas trap 11.

At the inner side of the container and round about it a partition 12 isprovided, in which a cylindrical cyclone inner mantle 13 is suspendedconcentrically.

With the aid of displacers 14 this inner mantle is centreted at thelower side within the container.

In the centre line of the container and the inner mantle a central body15 is mounted, which outwardly is provided with a helical rib 16 andwhose course is opposite to the direction the liquid takes when it flowsin through tangential supply duct 8.

Upper end 17 of this body extends into central gas discharge duct 10 andlower side 18 reaches beyond the lower edge of the inner mantle and endson bottom plate 6.

The liquid flows tangentially into the container via supply duct 8 sothat the entire container fills primarily round about the upper side.

The centrifugal action occurring here will allow an important part ofthe gas that is present in the liquid to escape primarily already pastcover lid 4 and central gas discharge duct 10 towards gas trap 11.

Because of the partition provided between the container and the innermantle the flow of liquid will be led over upper edge 19 of the innermantle and in this inner mantle make a downwardly directed helicoidalmovement past the inner wall of this mantle.

In the process, in the inner mantle a vortex pattern is created in whichthe gas that is being released from the flow of liquid proceeds to thecore.

Central body 15 arranged in this core zone will check and retard thedownward entrainment due to the course of its external helical rib, sothat the gas bubbles come to a standstill, liberate themselves from theliquid and escape via the central gas discharge duct.

The central body reaches as far as the bottom plate of the degasserspace so that a maximum effect of the above action is obtained.

Now the liquid flows between inner mantle l3 and outer mantle 1 towardstangential discharge duct 9, which is provided at a slight distanceunder partition 12.

Because of the application of the container with concentric inner mantleit is achieved that on the one hand the path of flow and so thedegassing traject of the liquid is long enough for a safe action of thedegasser, while on the other hand the device according to the inventioncan be rather short in respect of the devices known in the art with aslight difference in height between the supply and discharge ducts forthe liquid.

When the device described above is applied for degassing liquid sodium,as far as is possible welded joints instead of screwed or bolted jointsrespectively will be applied for the parts composing the degasser.

We claim:

1. A device for degassing liquids, while applying a cyclone, inparticular for removing an inert gas such as argon from liquid sodium,comprising a cylindrical container provided with a tangential supplyduct for the liquid to be degassed, a central discharge for the gas atthe upper side of the container, a cyclone mantle and a discharge ductfor the degassed liquid, wherein at the inner side of the container walla horizontal partition is provided that lies under the tangential supplyduct of the liquid, at which partition a cylindrical cyclone mantle isattached that is concentric with this container, which cyclone mantle isopen at the upper and lower sides and whose upper edge lies over thesupply duct and whose lower edge is situated near the bottom of thecontainer, while at a slight distance under the partition discharge ductfor the degassed liquid is connected to the space between the cycloneinner mantle and the container wall.

2. A device according to claim 1, wherein the control discharge duct forthe gas is situated centrally over the upper edge of the cyclone innermantle and has a diameter that is considerably smaller than the diameterof the inner mantle.

3. A device according to claim 1, wherein in the centre line of thecyclone inner mantle a central body is mounted that'externally isprovided with at least one helical rib whose course is opposite to thedirection of rotation of the liquid, which rotation is effected by thetangential supply duct.

l l II! *zgygg UNlTED s'm'nzs PATEN'}? OFFICE CERTIFICATE OF CORRECTIONPatent No, D t d NOVGmbQI' Inventor) Gerrit Marinus Wisman and PieterAdam. Van Rija rs in the above-identified patent It is certified thaterror appea by corrected as shown below:

and that said Letters Patent are here @rm mm Qglurm Line k I l After[21] Ap-pln :'r 187, 8 n s insert the following: [30] ForeignApplication Priority Date.

October 13,- 1970 he Nether ands ro-1 4976 IN PATENT APPLICATION ColumnLine Claim Line r I 30 l 1O "concentric" shoui d read I concentricalSigned and sealed this 9th day of. July 197 7 (SEAL) Attest:

' McCOY M. GIBSON, JR. r c. MARSHALL. 1mm Attesting Officer 4 iCommissioner I of Patents

1. A device for degassing liquids, while applying a cyclone, inparticular for removing an inert gas such as argon from liquid sodium,comprising a cylindrical container provided with a tangential supplyduct for the liquid to be degassed, a central discharge for the gas atthe upper side of the container, a cyclone mantle and a discharge ductfor the degassed liquid, wherein at the inner side of the container walla horizontal partition is provided that Lies under the tangential supplyduct of the liquid, at which partition a cylindrical cyclone mantle isattached that is concentric with this container, which cyclone mantle isopen at the upper and lower sides and whose upper edge lies over thesupply duct and whose lower edge is situated near the bottom of thecontainer, while at a slight distance under the partition discharge ductfor the degassed liquid is connected to the space between the cycloneinner mantle and the container wall.
 2. A device according to claim 1,wherein the control discharge duct for the gas is situated centrallyover the upper edge of the cyclone inner mantle and has a diameter thatis considerably smaller than the diameter of the inner mantle.
 3. Adevice according to claim 1, wherein in the centre line of the cycloneinner mantle a central body is mounted that externally is provided withat least one helical rib whose course is opposite to the direction ofrotation of the liquid, which rotation is effected by the tangentialsupply duct.